asID: Make a Valid Block Format ID From One or More Vectors
In benjaminrich/PCSmisc: Useful functions for longitudinal data set construction and manipulation.

Description Usage Arguments Value Author(s) See Also Examples

A block-format ID is constructed from one or more atomic vectors. If more than one atomic vector is supplied, then a compound ID is constructed by concatenating the values together.

1	asID(id, ..., sep="\|")

`id`	An atomic vector.
`...`	More atomic vectors.
`sep`	A character to use as a separator when forming a compound ID.

A valid block format ID, i.e. a factor x such that is.unsorted(x) is FALSE.

Ben Rich <[email protected]>

block-format

require(nlme)
data(Phenobarb)
dat <- Phenobarb[1:56,]  # First 4 subjects

attach(dat)

is.unsorted(Subject)           # TRUE  - the original column is NOT sorted
is.unsorted(asID(Subject))     # FALSE - the ID is sorted

all(as.character(Subject) == as.character(asID(Subject)))  # TRUE - textually they are the same

cbind(ID=asID(Subject), dat)

detach(dat)